Effects of Transcutaneous Electrical Nerve Stimulation on Pain, Pain Sensitivity, and Function in Patients With Knee Osteoarthritis: A Randomized Controlled Trial

Vance CGT et al. – When compared to P–Transcutaneous Electrical Nerve Stimulation (TENS), HF– and LF–TENS reduced pressure pain sensitivity le in knee OA subjects –P–TENS had no significant effect on pressure pain threshold (PPT). Cutaneous pain measures were unaffected by TENS. Subjective pain ratings at rest and during movement were similarly reduced by active and placebo TENS suggesting a strong placebo component to the effect of TENS.

Methods

• 75 subjects with knee osteoarthritis (31–94 years, M=29, F=46) were assessed.
• Subjects were randomly assigned to receive HF–TENS (100 Hz) (n=25), LF–TENS (4 Hz) (n=25) or Placebo (P) TENS (n=25) [pulse duration=100msec; intensity=10% below motor threshold].
• The following measures were assessed before and after a single TENS treatment: cutaneous mechanical pain threshold (CMPT), pressure pain threshold (PPT), heat pain threshold (HPT), heat temporal summation (HTS), Timed Up and Go (TUG) test, and pain intensity at rest and during the TUG test.
• A linear mixed model ANOVA compared differences before and after TENS, and between groups (HF, LF, and P).

Results

• When compared to P–TENS, HF–TENS and LF–TENS increased PPT at the knee; HF–TENS also increased PPT over the anterior tibialis muscle.
• There was no effect on CMPT, HPT, or HTS. HF–, LF– and P–TENS significantly reduced the pain at rest and during the TUG test.

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